Disk drives using various kinds of disks, such as optical disks, magneto-optical disks, flexible magnetic-recording disks, and similar data-storage disks are known in the art. In particular, hard-disk drives (HDDs) have been widely used as indispensable data-storage devices for contemporary computer systems. Moreover, HDDs have found widespread application to motion picture recording and reproducing apparatuses, car navigation systems, cellular phones, and similar devices, in addition to the computers, due to their outstanding data-storage characteristics.
A magnetic-recording disk used in a HDD includes multiple concentric data tracks and servo tracks. A servo track includes multiple servo sectors having address information. A data track includes multiple data sectors containing user data. A data sector is recorded between separate servo data regions in the circumferential direction. A read element, or alternatively, a write element, of a magnetic-recording head of a head-slider supported by a rotary actuator accesses designated data sectors according to address information in servo sectors to write data to, and read data from, data sectors.
In order to increase the recording density of a magnetic-recording disk, the clearance between the read element, or alternatively, the write element, of the magnetic-recording head of the head-slider, flying in proximity to the recording surface of the magnetic-recording disk, and the magnetic-recording disk is decreased; and, variations in the clearance are also decreased. To this end, some mechanisms have been proposed to control the clearance. One such mechanism, which is referred to herein by the term of art, “thermal fly-height control,” or “TFC,” includes a heater on a head-slider; the heater heats the read element, or alternatively, the write element, of the magnetic-recording head of the head-slider and the surroundings to adjust the clearance. TFC generates heat by applying electrical current to the heater to cause the read element, or alternatively, the write element, of the magnetic-recording head to protrude by thermal expansion. This decreases the clearance between the magnetic-recording disk and the magnetic-recording head. Other mechanisms are known in the art that use a piezoelectric element, or alternatively, coulomb force, to adjust the clearance between the magnetic-recording disk and the magnetic-recording head.
Engineers and scientists engaged in HDD manufacturing and development are interested in the design of HDDs that control the clearance and variations in the clearance between the magnetic-recording head of the head-slider and the magnetic-recording disk to meet the rising demands of the marketplace for increased data-storage capacity, performance, and reliability.